Re: [PATCH v3 1/2] acpi/nfit: Update nfit driver to comply with ACPI 6.1

From: Dan Williams
Date: Tue Jun 19 2018 - 11:28:48 EST


On Tue, Jun 19, 2018 at 7:31 AM, Elliott, Robert (Persistent Memory)
<elliott@xxxxxxx> wrote:
>
>
>> -----Original Message-----
>> From: Dan Williams [mailto:dan.j.williams@xxxxxxxxx]
>> Sent: Monday, June 18, 2018 4:47 PM
>> To: Elliott, Robert (Persistent Memory) <elliott@xxxxxxx>
>> Cc: Kani, Toshi <toshi.kani@xxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; linux-
>> nvdimm@xxxxxxxxxxxx; Moore, Robert <robert.moore@xxxxxxxxx>; Li, Juston
>> <juston.li@xxxxxxxxx>; rjw@xxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx
>> Subject: Re: [PATCH v3 1/2] acpi/nfit: Update nfit driver to comply with
>> ACPI 6.1
>
>
>> Let's take something simple like Vendor ID. What is the Vendor ID for
>> these DIMMs and what does Linux print in sysfs?
>
> Here are some examples (kernel 4.17):
>
> $ cd /sys/bus/nd/devices/nmem0/nfit
> $ grep -s . *
> device:0x314e
> dsm_mask:0x3c76
> family:1
> flags:smart_notify
> format:0x0101
> formats:1
> handle:0x1
> id:802c-0f-1612-122f8255[SPD bytes 320-328, in that order left-to-right]
> phys_id:0x16
> rev_id:0x3100
> serial:0x122f8255
> subsystem_device:0x3141
> subsystem_rev_id:0x0100
> subsystem_vendor:0x8034[Cypress Semiconductor]
> vendor:0x802c[Micron]

Ok, so the lowest significant byte of the Micron id is supposed to be
0x2c and this text representation matches that. So the bytes are being
endian swapped when written to the SPD?